Fermentation

1
Fermentation

• Definition and Types

2
Fermentation

• In practice, fermentation is an art.
• Encourage growth of the right microorganisms and
  discourage growth of microorganisms that cause
  spoilage.
• Accomplished by adding salt or a starter culture
  to the food, or in some cases slightly acidifying
  it.

3
What is it?

• Enzymatically controlled change in food
• Caused by microbes
• Changes caused by
• Break down of components
• Glucose ? Pyruvate ? acid or alcohol CO2
• Release of by-products

4
By-Products -- Changes and Advantages

• Changes
• Color
• Texture
• Flavor
• Aroma
• pH
• Advantages
• New products
• Increases shelf-life
• Increases variety of food products available

5
Starter Culture

• A starter culture can be
• Yeast,
• Bacteria, or
• Mold
• Influence quality characteristics such as
• texture, moisture content, no pathogens and
  their toxins, and taste.

6
Uses in the food industry
End product Raw ingredient Starter culture
Beer Barley and hops Yeast
Bread Sugar in dough Yeast
Yogurt Milk Bacteria
Cheese Milk Bacteria
Pickles Cucumber Bacteria
Vinegar Cider, wine Bacteria
7
Yeast Fermentation

• Saccharomyces cerevisiae
• Uses sugar as fuel
• A fungus
• Food products
• Yeast breads
• Alcoholic beverages

8
Bacterial Fermentation

• Lactic Acid
• Pickled vegetables (cabbage, cucumbers, olives)
• Semi dry and dry sausages
• Cultured dairy products
• Acetic Acid
• Two step process (yeast creates wine)
• Acetic acid bacteria creates vinegar

9
Mold Fermentation

• Antibiotics
• Flavor compounds
• Enzymes
• Two-step fermentation with mold includes
  chocolate and cheeses
• Products
• Tempeh
• Soy sauce

Tempeh
Soy sauce